Convac System – A New Age Solution for Complete Waterproofing & Damp-proofing

ConstruCtion ChemiCals and Waterproofing

Waterproofing of any structure is an essential factor

for long-term durability and performance. Structural

design and construction are key elements of a

project and it demands significant technical attention. Moisture

infiltration and humidity can cause severe damage and if excess

water is present the impact of the same can be catastrophic

at times, it can lead to structural failure or it can become

uninhabitable.

The objective of this technical paper is to explore building

materials and its characteristics, waterproofing and its implication,

types of waterproofing systems available and their limitations. In

addition to these, the paper will be introducing CONVAC SYSTEM

to the readers.

One of the basic and fundamental requirements of any

building is that the structure should remain dry as far as possible.

Seepage in building is a very common phenomenon and it is very

important to understand the causes and preventive measures to

be followed. A well designed building should take the following

factors into consideration during planning:

- The properties and behaviour of the building materials used

- The initial and long-term cost implications

- The effect of the environment

- How the materials react with each other

Most of the building materials have pores in their structure in

the form of intermolecular spaces; for example concrete, mortar,

burnt clay, bricks, etc. They expand on absorbing moisture from

atmosphere and shrink on drying.

Building materials absorb water from atmosphere or from

some other external source(s); once the structure becomes

saturated seepage can occur through the building components like

walls, RCC members, roof terrace, plasters, etc. Another major

reason of seepage is the porosity of the building materials when

buildings are exposed to atmosphere; water is absorbed by the

materials gradually and results in seepage through roof terrace

and walls exposed to atmosphere.

When considering a waterproofing system to control liquid

penetration, it is important to look at two factors that allow for

the movement of water. These are hydrostatic pressure and

capillarity action.

– Hydrostatic pressure is the pressure coming from the weight

of the liquid and its value is directly proportional to the height

of the liquid and the density of the liquid. A dense liquid will

produce a greater hydrostatic pressure. In scientific terms,

hydrostatic pressure increases in proportion to the depth

measured from the surface because of the increasing weight

of fluid exerting downward force from above.

– Capillarity is the force that results from greater adhesion

of a liquid (water) to a solid surface than internal cohesion

of the liquid itself and is therefore able to literally rise along

vertical surfaces. What does it mean? Basically it means that

liquid rises against gravity. The amount of capillary rise is

determined by the space between the particles, or if you are

looking at tubes, a tube with a smaller diameter will produce a

greater rise. When selecting granular materials for drainage,

if the space between the aggregates is larger, lesser will be

the potential for capillary rise, and also water will drain freely

through those spaces.

Dampness in Buildings- Defects As After Effects

Various defects caused by dampness to a building can be

summarized as follows:

- It causes efflorescence, which may ultimately result in

disintegration of bricks, stones, tiles etc.

- It may result in softening and crumbling of plaster.

- It may cause bleaching and flaking of paint leading to patches.

- It may result in the warping, buckling and rotting of timber.

- It may lead to corrosion of metals.

- It may cause deterioration to electrical fittings and fixtures.

- It promotes growth of termites and fungus.

- It creates unhealthy living condition for the occupants.

- It increases building maintenance cost, which is unplanned.

- Last but not the least it severely affects the aesthetics of the

building.

Dampness in Buildings- Sources

The important sources of dampness are:

- Dampness rising through the foundation walls: Moisture from

wet ground may rise well above the ground level on account

of capillary action.

90 CE&CR sEPTEMBER 2015

As has been mentioned earlier there is no single universal

waterproofing system that can work in all situations. It would be

great if there was as it would make life very easy. CONVAC and

CONVAC PLUS are now available, which, as we claim are complete

waterproofing cum damp proofing system. When selecting

this system, it is important to understand if the waterproofing

system is considered to be on the positive side or negative

side waterproofing system. What does that mean? In general,

negative side waterproofing means that the waterproofing layer

is applied to that side of the construction member, which is

opposite to the side that is in direct contact with water. Reverse

of the same is positive side waterproofing. It is always advisable

to do the waterproofing system from the positive side for better

results. Only if the positive side is inaccessible negative side

waterproofing is to be done.

CONVAC SYSTEM can be applied on both sides of

waterproofing system wherever needed. Hence application scope,

suitability and ease of application with CONVAC SYSTEM is more

compared to products available in the market.

CONVAC SYSTEM is an innovative solution for concrete and

masonry works. This system densifies the concrete or mortar

matrix to an optimum level and permeability of liquid water, which

carries electrolytes is reduced to practically nil.

Typical Water Proofing system is carried out through the

following procedures

- Surface preparation

- Crack treatment

- Product application

- Protection plaster / screed

With the CONVAC SYSTEM we can directly avoid some

operations, which saves both cost and time:

- Surface preparation

- Crack treatment

- Splashing rain water which rebounds after hitting the wall

surface.

- Penetration of rain water through unprotected wall tops,

parapet, compound walls, etc.

- In case of sloped roofs, rain water may percolate through

defective roof covering. In addition faulty eaves course and

eave or valley gutters may allow the rain water to descend

through the top supporting wall and cause dampness.

- In case of flat roofs, inadequate roof slopes, improper

rainwater pipe connections, and defective junction between

roof slab and parapet wall may prove to be the source of

dampness.

No matter how good the waterproofing system is, one major

factor that controls everything is the waterproofing details. This

can be from design right through to construction, if the detailing

is lacking, water will find its way in.

When selecting the correct system, it is very important to

differentiate between waterproofing and damp proofing. These

terms are sometimes misunderstood and can cause the selection

of improper materials when trying to control moisture intrusion.

- Waterproofing is defined as the resistance of the passage of

water under hydrostatic head pressure.

- Damp proofing is defined as the resistance of water in the

absence of hydrostatic head pressure. Damp proofing

materials typically will not bridge cracks in concrete that

may occur during the life of a building. It is very important

to understand this, as without proper drainage there can be

presence of hydrostatic pressure.

Till yesterday there was no single product solution that

was suitable for every situation, so selection of a suitable

waterproofing system should depend on the requirements of the

project. Some common characteristics that should be considered

are whether the system is effective against moisture intrusion,

be it waterproofing, damp proofing or capillary action. Water will

find a way in if there are inconsistencies in the system. It needs to

be durable both during and after construction and definitely need

to be robust and durable for the life of the structure. Having a

premature failure of a waterproofing system can be catastrophic

and costly. Ideal waterproofing is a combination of quality product

backed by excellent and trained application team.

CONVAC PLUS and CONVAC are an innovative and first

of its kind patented product systems, which can act against

Waterproofing and Damp Proofing both during and after

construction.

ConstruCtion ChemiCals and Waterproofing

CE&CR sEPTEMBER 2015 91

Thus it can be firmly concluded that CONVAC SYSTEM is the

ultimate and preferred choice as it gives complete solution, it is

cost effective and chances of failure is reduced considerably.

The CONVAC SYSTEM: Waterproofing Additive for Impermeable Mortars and Plasters

CONVAC SYSTEM is a waterproofing additive in semi liquid

form for mortars and concretes. It does not modify the setting

time, the hardening time but increases the final strength of

cement mixtures.

Thanks to its unique and innovative formulation, CONVAC

SYSTEM gives hardened mortars and concretes excellent

impermeability to beating and counter thrusting water (more

than four bars), therefore it is particularly suitable for internal

/external plasters and concretes and to make foundations.

CONVAC SYSTEM as an integral waterproofing product: It

is possible to waterproof the whole thickness of the concrete,

thus shielding it from attack of aggressive and polluted

waters and protecting the steel reinforcements of the whole

structure.

The foundations of the buildings, which form the walls of

basements and garages, do not require any further waterproofing

treatment if the concrete is made with the addition of CONVAC

SYSTEM. It is important to remember that to ensure good

waterproofing, concrete must be properly planned and has a

dosage of cement not lower than 300 kg/m3, and then CONVAC

SYSTEM becomes highly effective.The intrusion of foreign bodies

such as wood, soluble materials, porous materials and loose

stones into the concrete may jeopardize the impermeability of the

structure.

Unlike many “ready-to-use” products available in the market,

CONVAC SYSTEM makes plasters easily applicable to further

masonry work and its high adhesive nature lowers rebound loss.

Please note that, after a treatment with silicone solutions it

never allows any subsequent treatment, the plasters made with

CONVAC SYSTEM allow any kind of surface treatment without

any problems.

Rising Damp Test on Concrete Cube: Rising Damp is almost nil with the use of CONVAC PLUS (dosage of 1% BOWC)

For further details visit http://atplgroup.in/ or write to atplkolkata@gmail.com

ConstruCtion ChemiCals and Waterproofing

92 CE&CR sEPTEMBER 2015

Mr Mrinal Roy, R&D & QC, ADO Additives Mfg Pvt. Ltd, Kolkata

TEST NAME OBSERVATION

Gripping Power With C:S = 1:3 On A Glass Plate (5% Dosage)

After 24 hrs no separation found from the glass plate

Hair Line Crack With Cement Paste

No crack developed in 24 hrs

Test Of Reducing Rebound Loss In Mortar With C:S=1:3 (2% Dosage)

Mortar did not fall in 60 sec-onds in vertical position

Water Absorption (%) With 1% dosage of CONVAC PLUS : 0.60%Control : 3.80%

Water Penetration (Avg.) Din 1048

With 2% dosage of CONVAC PLUS : 30 mmControl : 145 mm

Test Results:

Concrete Test Result

(Unit : kg/m3)

W/C Cement (UltraTech

OPC)

Fly Ash

Sand (Z-II)

CA 10mm

CA 20mm

Water PCE Based Admixture

CONVAC PLUS

1 Day Compressive

Strength

3 Day Compressive

Strength

7 Day Compressive

Strength

28 Day Compressive

Strength

0.4 255 135 692 492 705 190 1.95 0 4.44 mPa 18.67 mPa 20.89 mPa 47.45 mPa

0.4 255 135 692 492 705 190 1.95 1.275 7.11 mPa 24.00 mPa 29.33 mPa 54.00 mPa

% Gain in Compressive Strength with the use of CONVAC PLUS compared to CONTROL MIX 60 % 28.50 % 40.40 % 13.80 %(All technical data stated herein are based on tests carried out under laboratory condition)